38 results about "Peptide mass" patented technology

Methods of analysing peptides by mass spectrometry are disclosed. In particular, methods of analysing peptides by fragmentation mass spectrometry (MSn, where n is at least 2) are disclosed. The methods involve derivatisation of a peptide at its N-terminus such that peaks corresponding to both a and b (and y) daughter ions are identifiable in fragmentation mass spectra of the derivatised peptide. The fragmentation mass spectra of the derivatised peptide contain additional information (relative to the fragmentation mass spectra of the underivatised peptide) useful for determination of the amino acid sequence of the peptide.

The present invention relates to a method for phosphorylation site-specific labeling of phosphoproteome with a site-specific tagging reagent and analyzing of the resulting labeled one, more especially, a method for in-situ tagging of phosphorylation sites of phosphoproteins retained in polymeric gel with a nucleophilic tagging reagent. It also relates a method for generating new proteolytic cleavable sites at formerly phosphorylation sites by a proper choice of a nucleophilic tagging reagent. It also relates to a method for phosphopeptides analysis and phosphorylation site identification by in-gel digestion of the previously in-gel tagged proteins and subsequent mass analysis of the resulting peptides. The invention provides in-gel chemical tagging method for phosphoaminoacid residue of phosphoproteins retained in polymeric gel matrix. Phosphoprotein can be immobilized into gel matrix by a variety of methods such as gel electrophoresis. The immobilized phosphoproteins are retained in gel matrix during tagging reaction to phosphorylated aminoacid residue of phosphoproteins, and the resulting tagged proteins are also retained in gel matrix till following purification steps like washing of the tagging reagents are accomplished. The tagged proteins is digested by protease, and the resulting digested peptides is released from gel into solution and applied for peptide mass analysis.

The invention relates to a mass spectrometry calibration system that may be performed in real-time using the information contained within a sample without the addition of specific calibrants. When applied to a sample, such as a proteomic sample, the calibration system may identify the exact masses of peptides in the sample. The system involves the use of mathematical algorithms that iteratively estimate the error in the measurement and update the calibration parameters accordingly; thereby resulting in peptide mass identification.

Proteolytic peptide mass mapping as measured by mass spectrometry provides an important method for the identification of proteins, which are usually identified by matching the measured and calculated m / z values of the proteolytic peptides. A unique identification is, however, heavily dependent upon the mass accuracy and sequence coverage of the fragment ions generated by peptide ionization. The present invention describes a method for increasing the specificity, accuracy and efficiency of the assignments of particular proteolytic peptides and consequent protein identification, by the incorporation of selected amino acid residue(s) enriched with stable isotope(s) into the protein sequence without the need for ultrahigh instrumental accuracy. Selected amino acid(s) are labeled with 13C / 15N / 2H and incorporated into proteins in a sequence-specific manner during cell culturing. Each of these labeled amino acids carries a defined mass change encoded in its monoisotopic distribution pattern. Through their characteristic patterns, the peptides with mass tag(s) can then be readily distinguished from other peptides in mass spectra. The present method of identifying unique proteins can also be extended to protein complexes and will significantly increase data search specificity, efficiency and accuracy for protein identifications.

A method for acquiring and analyzing polypeptide mass spectra comprising: creating first and second sets of fragmented ions using first and second fragmentation techniques; obtaining mass spectra of the first and second sets of fragmented ions; searching a database of fragments of a first fragment pair type and of a second fragment pair type to respectively provide a set of M ranked and a set of N ranked best matching polypeptide sequences; subtracting synthetic spectra corresponding to each of the M and N ranked sequences from the mass spectra to provide first and second sets of modified mass spectra; searching the database of fragments of the second fragment pair type and of the first fragment pair type to provide third and fourth sets of polypeptide sequences providing best matches to the first and second sets of modified spectra, respectively; and creating a cumulative ranking of the third and fourth sets.

The present invention belongs to the field of plant protein separating and purifying technology, and is ginkgo protein GAP IIa separated from gingko and with functions of delaying senility and resisting oxidation and its preparation process and use. The present invention via the process of salt separation, salt dissolution, two-step ion exchanging chromatography and other steps, new protein GAP IIa of molecular weight 29248 Da is separated from gingko and purified. The primary structure and spatial structure detection shows that GAP IIa consists of two peptide chains, GAP IIa-1 and GAP IIa-2, with similar molecular weight and similar amino acid sequence and connected via disulfide bond and with a few glycosyl via O-glycosidic bond. Each of GAP IIa-1 and GAP IIa-2 contains peptide segments of peptide mass number of 911, 1-11 and 2470. The ginkgo protein may be used in producing health food and medicine for resisting oxidation and delaying senility.

The present disclosure relates to methods of improved identification of peptides, for example, antigenic peptides. In particular, the present disclosure relates to methods of more accurately identifying human leukocyte antigen (HLA) peptides by utilizing classification systems. The disclosure also provides for utilizing the described methods for the field of personalized cancer therapies, such as adoptive cellular therapy (ACT).

The invention discloses a collagen zymolyte with a blood sugar reducing effect and a preparation method and application thereof, the zymolyte contains Gly-Pro-type peptide composed of 4-7 amino acid residues, and the mass ratio is 30-45%; the general formula of the sequence of the Gly-Pro-type peptide consisting of 4 to 7 amino acid residues is Gly-Pro-Xaa1-Gly-[Xaa2] r-[Xaa3] s-[Gly] t. According to the preparation method provided by the invention, the zymolyte with strong DPP-IV inhibition activity is prepared for the first time, and the DPP-IV inhibition rate of the zymolyte is as high as 68% when the final concentration is 1mg / mL; the zymolyte is rich in Gly-Pro-type peptide composed of 4-7 amino acid residues, and the peptide yield is as high as 45%; animal experiments prove that the zymolyte can regulate fasting blood-glucose of rats with type 2 diabetes mellitus and improve the oral glucose tolerance of the rats with type 2 diabetes mellitus.

A glycopeptide analyzer that performs a structural analysis on glycoforms of a glycoprotein, including: a spectrum creator creating an MS / MS spectrum for each elution time based on data acquired by an LC / MS analysis of a sample containing glycopeptides originating from a target glycoprotein; a peptide mass calculator selecting a glycopeptide-related spectrum from a plurality of MS / MS spectra and calculating the mass of a peptide from the selected spectrum; a similarity determiner determining a similarity between the glycopeptide-related spectrum and each of the other MS / MS spectra; an elution-time range estimator estimating an elution-time range based on a distribution of the frequency of occurrence of an MS / MS spectrum for which a high level of similarity has been determined on a time axis; and a glycan composition estimator selecting an ion peak corresponding to a mass equal to or greater than a peptide mass and estimating a glycan composition based on the peak.

The invention relates to a reagent for cutting peptides, in particular to a reagent for cutting sulfydryl-containing peptides from resins. In addition, the invention also relates to a method for cutting sulfydryl-containing polypeptides from resins, which is suitable for industrial production of sulfydryl-containing polypeptides. The reagent for cutting sulfydryl-containing polypeptides from resins comprises the following components in parts by weight: 85-95 parts of trifluoroacetic acid, 1-5 parts of triisopropylsilane, 1-4 parts of mercaptoundecanoic acid, 1-4 parts of phenol and 1-2 parts of water. The invention has the advantages that because ethanedithiol is a chemical reagent which is not produced at home, the cost of the ethanedithiol is expensive, and the ethanedithiol has effluvial smell in the reaction process; in the invention, mercaptopropionic acid is used for replacing the conventional ethanedithiol, thus the production cost can be lowered, the environment pollution is greatly reduced, and simultaneously, the effect of the peptide cutting reaction can also be improved; and meanwhile, the invention has the characteristics of low procurement cost, reduction of the three wastes, good crude peptide quality and the like, and is very suitable for industrial production of sulfydryl-containing polypeptides.

The present invention provides a preparation, which relates to the field of medicine, that is, the new pharmaceutical composition has bactericidal, especially, antibacterial and antiviral effects. A preparation of the present invention, containing blowfly antiviral peptide similar drug peptide H 2 N‑His‑Gly‑Val‑Ser‑Gly‑His‑Gly‑Gln‑His‑Gly‑Val‑His‑Gly‑COOH– and peptide HN 2 -(CH 2 ) 10 ‑CO‑Ile‑Leu‑Pro‑D‑Phe‑Lys‑D‑Phe‑Pro‑D‑Phe‑D‑Phe‑Pro‑D‑Phe‑Arg‑Arg‑NH 2 The mass ratio is 1:2 to 2:1 and auxiliary materials. In summary, the preparation has comprehensive antibacterial and antiviral effects, and the preparation (injection, gel, ointment, spray, etc.) can be used to treat herpes virus infection, vaginal herpes infection, HPV virus infection, and bacterial infection.

A method for preparing antioxidant peptides by using Bacillus subtilis to ferment rice dregs, the method is to first prepare Bacillus subtilis seed culture solution, then insert it into a fermentation medium, and carry out shaking table fermentation culture to obtain a fermentation solution; Enzyme, cooled to room temperature, centrifuged to remove bacteria and unfermented rice dregs, filtered the obtained fermentation supernatant, concentrated the filtrate, and freeze-dried. The invention uses rice dregs as raw materials to prepare antioxidant peptides, which has wide sources and low price, not only reduces the production cost of preparing antioxidant peptides, but also effectively comprehensively utilizes the by-product rice dregs, increases the added value of rice dregs, and expands its application range. Realize the large-scale industrial production of rice dregs antioxidant peptides. The product rice dregs protein antioxidant peptide prepared by the method of the invention has good quality, high antioxidant activity and strong reducing ability.

The invention relates to a method for extracting characteristic parameters of peptide mass spectrum peaks. The existing method has the disadvantage that it is difficult to ensure the accuracy of the extracted mass spectrum peak characteristic parameters when there is a large deviation in the distribution of the various points that form the peak in the peptide mass spectrum. The present invention proposes a method for extracting characteristic parameters of peptide mass spectrum peaks based on a nonlinear fitting method, using multiple sample point data, guided by the minimum difference between the actual data and the fitting result, and adopting an iterative method to continuously update the estimated value of the characteristic parameters, Until the convergence condition is satisfied, the final characteristic parameter estimation is obtained. This method can effectively reduce the adverse effects of the sample point distribution deviation on the solution of the characteristic parameters of the Gaussian curve, improve the numerical accuracy of the characteristic parameters, and then help improve the accuracy of peptide identification.

It is an object of the present invention, when determining and identifying an amino acid sequence of a peptide using MS, to obtain additional information from the MS for evaluating validity of an amino acid sequence in a candidate list outputted from an identifying engine. The present invention provides a method of testing an amino acid sequence inferred by searching a peptide-related database based on peptide mass information and / or peptide modification information obtained through mass spectrometry on a peptide, the method comprising the steps: (1) calculating a theoretical value of an isotopic ratio for the peptide from the inferred amino acid sequence and / or the peptide modification information; (2) measuring a measured value of the isotopic ratio for the peptide from the peptide mass information; and (3) comparing the theoretical value and the measured value, and evaluating validity of the inferred amino acid sequence from differences between the theoretical value and the measured value.

The invention provides a crosslinking dipeptide rapid identification method, comprising: 1) extracting effective spectrum peaks in a to-be-identified series-connected spectrogram, according to mass corresponding to each effective spectrum peak, searching a fragment index, to obtain a corresponding peptide fragment sequence as a candidate [alpha] peptide sequence, wherein the fragment index records mass of each fragment and the peptide fragment sequence corresponding to the mass of each fragment; 2) for each candidate [alpha] peptide sequence, according to parent ion mass of the to-be-identified series-connected spectrogram, calculating corresponding [beta] peptide mass, to obtain a corresponding candidate [beta] peptide sequence, combining the candidate [alpha] peptide sequence with the corresponding candidate [beta] peptide sequence, to obtain candidate crosslinking dipeptide; 3) matching the candidate crosslinking dipeptide obtained in the step 2) with the series-connected spectrogram in a fine manner, to obtain an identification result. The method does not need to use a special cross-linking agent, searching speed is fast, identification efficiency is high, and search sensitivity is high.

The present invention belongs to the field of plant protein separating and purifying technology, and is ginkgo protein GAP IIa separated from gingko and with functions of delaying senility and resisting oxidation and its preparation process and use. The present invention via the process of salt separation, salt dissolution, two-step ion exchanging chromatography and other steps, new protein GAP IIa of molecular weight 29248 Da is separated from gingko and purified. The primary structure and spatial structure detection shows that GAP IIa consists of two peptide chains, GAP IIa-1 and GAP IIa-2, with similar molecular weight and similar amino acid sequence and connected via disulfide bond and with a few glycosyl via O-glycosidic bond. Each of GAP IIa-1 and GAP IIa-2 contains peptide segments of peptide mass number of 911, 1-11 and 2470. The ginkgo protein may be used in producing health food and medicine for resisting oxidation and delaying senility.